1. Field of the Invention
The present invention relates to a product (including a machine, a manufacture, and a composition of matter) and a process (including a simple process and a production process). In particular, one embodiment of the present invention relates to a semiconductor device, a display device, a light-emitting device, a power storage device, a driving method thereof, or a manufacturing method thereof. In particular, one embodiment of the present invention relates to a semiconductor device, a display device, or a light-emitting device, which includes an oxide semiconductor.
2. Description of the Related Art
Oxide semiconductors have recently attracted attention as materials for next-generation thin film transistors. Examples of oxide semiconductors include tungsten oxide, tin oxide, indium oxide, zinc oxide, and the like, and there are known thin film transistors in which such oxide semiconductors are used in channel formation regions.
As oxide semiconductors, not only single-component oxides but also multi-component oxides are known. In particular, an In—Ga—Zn—O-based oxide material (hereinafter also referred to as IGZO) has been actively studied.
Patent Document 1 discloses a technique by which a conductive film including a metal, a metal compound, or an alloy that can absorb or adsorb moisture, a hydroxy group, or hydrogen is formed to overlap with an oxide semiconductor film with an insulating film provided therebetween.
Patent Document 2 discloses a technique by which hydrogen in a film and at an interface between films is removed in a transistor using an oxide semiconductor.